Trace gas emissions from soil of the central highlands of Mexico as affected by natural vegetation: a laboratory study     

M.?V.?Angoa?Pérez  J.?Gonzalez?Casta?eda  J.?T.?Frías-Hernández  O.?Franco-Hernández  O.?Van?Cleemput  L.?DendoovenEmail author  V.?Olalde 《Biology and Fertility of Soils》2004,40(4):252-259

In the central highlands of Mexico, mesquite (Prosopis laevigata) and huisache (Acacia schaffneri), N₂-fixing trees or shrubs, dominate the vegetation and are currently used in a reforestation program to prevent erosion. We investigated how natural vegetation or cultivation of soil affected oxidation of CH₄, and production of N₂O. Soil was sampled under the canopy of mesquite (MES treatment) and huisache trees (HUI treatment), outside their canopy (OUT treatment) and from fields cultivated with maize (ARA treatment) at three different sites while production of CO₂, and dynamics of CH₄, N₂O and inorganic N (NH₄⁺, and NO₃^–) were monitored in an aerobic incubation. The production of CO₂ was 2.3 times higher and significantly greater in the OUT treatment, 3.0 times higher in the MES treatment and 4.0 times higher in the HUI treatment compared to the ARA treatment. There was no significant difference in oxidation of CH₄ between the treatments, which ranged from 0.019 g CH₄–C kg^–1 day^–1 for the HUI treatment to 0.033 CH₄–C kg^–1 day^–1 for the MES treatment. The production of N₂O was 30 g N₂O–N kg^–1 day^–1 in the MES treatment and >8 times higher compared to the other treatments. The average concentration of NO₃^– was 2 times higher and significantly greater in the MES treatment than in the HUI treatment, 3 times greater than in the OUT treatment and 10 times greater than in the ARA treatment. It was found that cultivation of soil decreased soil organic matter content, C and N mineralization, but not oxidation of CH₄ or production of N₂O.  相似文献   

Compost Effects on Soil Physical Properties And Field Nursery Production     

R.F. Gonzalez  L.R. Cooperband 《Compost science & utilization》2013,21(3):226-237

Field production of ornamental shrubs often results in significant topsoil removal and degradation of surface soil physical properties. Building soil organic matter through compost amendments is one way to ameliorate effects from topsoil removal in woody ornamentals production. We amended field soils with three composts to evaluate their effects on soil physical properties and shrub biomass production. Specifically, we applied either duck manure-sawdust (DM), potato cull-sawdust-dairy manure (PC) or paper mill sludge-bark (PMB) composts to a Plano silt loam soil using two application methods: 2.5 cm of compost incorporated into the top 15 cm of soil (incorporated-only) or 2.5 cm of compost incorporated plus 2.5 cm of compost applied over the soil surface (mulched). We grew three shrub species from liners: Spirea japonicum ‘Gumball’, Juniper chinensis ‘Pfitzeriana’, and Berberis thunbergia ‘Atropurpurea’. Shrub species and soil amendment treatments were established in triplicate in a randomized split plot design. Total soil carbon (TC), bulk density (ρb), aggregate stability, soil moisture retention capacity (MRC), volumetric moisture content (θ_v), and saturated hydraulic conductivity (K_sat) were measured over three years (1998 to 2000). We measured above and below ground shrub dry matter production at the end of the first (1998) and second (1999) growing seasons. Mulched treatments resulted in 15%-21% higher TC than the incorporated-only and no-amendment control treatments. Bulk density decreased with increasing TC contents. Greater aggregate stability and the formation of larger aggregates were related to increased TC. Field moisture retention capacity tended to be higher in the incorporated treatments compared to the mulched and nonamended control treatments. Compost amended treatments increased saturated hydraulic conductivity (K_sat) sevenfold over the nonamended control. There were no compost effects on shrub biomass until the second year of growth. Barberry was the only species to respond significantly and positively to compost application. Specifically, mulched DM compost produced 39-42% greater total Barberry biomass than the other compost treatments and the nonamended control. Our findings showed that compost effects on soil physical properties differed among composts and their subsequent effects on shrub growth were species specific.  相似文献   

Residual effects of organic Zn fertilizers applied before the previous crop on Zn availability and Zn uptake by flax (Linum usitatissium)     

Patricia Almendros  Demetrio Gonzalez  Jose M. Alvarez 《植物养料与土壤学杂志》2013,176(4):603-615

The objective of this study was to compare the residual effect of zinc (Zn) from three Zn chelates (Zn‐aminelignosulfonate, Zn‐AML; Zn‐polyhydroxyphenylcarboxylate, Zn‐PHP; and Zn‐ethylenediaminedisuccinate, Zn‐EDDS), applied at two rates (5 and 10 mg Zn [kg soil]^–1, respectively) to a previous crop, for a flax crop (Linum usitatissimum L.). For the greenhouse experiment, two different soils were used: a weakly acidic soil, classified as Typic Haploxeralf (Soil_acid), and a calcareous soil, classified as Typic Calcixerept (Soil_calc). Plant availability of soil Zn was evaluated using the DTPA‐triethanolamine (TEA), Mehlich 3, and low‐molecular‐weight organic acids (LMWOAs) methods. Easily leachable Zn was determined, and soil Zn status was characterized based on the Zn distribution in different fractions obtained by a sequential extraction. The Zn reserves after the previous crop were substantial and ranged from 2.85% to 5.61% of available Zn (Mehlich 3‐extractable) with respect to the applied Zn. Plant parameters such as dry‐matter yield, total Zn, and soluble Zn concentrations were measured, and Zn utilization by plants was calculated. In both soils, the highest concentrations of available Zn were associated with the application of Zn‐AML at a rate of 10 mg Zn kg^–1. In Soil_acid the largest quantity of easily leachable Zn was also observed with Zn‐AML fertilizer. Similarly, Zn‐AML resulted in the highest Zn concentration in flax seeds (229 mg Zn kg^–1 and 72 mg Zn kg^–1 for the highest rate of Zn application to Soil_acid and Soil_calc, respectively). The results suggest that these Zn chelates resulted in a residual effect in soils with appropriate concentrations of the most labile fractions of Zn and available Zn, particularly when Zn‐AML was applied at the highest rate. This chelate was more effective in Soil_acid than in Soil_calc. In the weakly acidic soil at the lowest Zn level it was associated with the highest percentage of Zn utilization by the flax plant and the most effective Zn transfer from soil to the plant.  相似文献   

Predictive value of prepartum serum metabolites for incidence of clinical and subclinical mastitis in grazing primiparous Holstein cows     

Elizabeth Schwegler  Augusto Schneider  Paula Montagner  Diego Andres Velasco Acosta  Luiz Francisco Machado Pfeifer  Eduardo Schmitt  Viviane Rohrig Rabassa  Francisco Augusto Burkert Del Pino  Helenice de Lima Gonzalez  Cláudio Dias Timm  Marcio Nunes Corrêa 《Tropical animal health and production》2013,45(7):1549-1555

The aim of this study was to measure changes in biochemical markers in the peripartum period of primiparous Holstein cows diagnosed with subclinical and clinical mastitis. In this study, 37 dairy cows were monitored daily during milking until 60 days postpartum and were categorized according to the occurrence of clinical mastitis (group mastitis (GM), n?=?9) or subclinical mastitis (group subclinical mastitis (GSUB), n?=?10) or absence of symptoms (control group (CG), n?=?18). Blood samples were collected weekly from ?30 to 60 days from calving. Samples were grouped for prepartum (?30 to 0 days from calving), early postpartum (0 to 30 days from calving), and late postpartum (30 to 60 days from calving) periods. Prepartum serum non-esterified fatty acid (NEFA) concentration was higher in GM than in CG (P?<?0.01). In addition, CG had higher prepartum serum glucose concentration than GM (P?=?0.03). In the early postpartum period, aspartate aminotransferase (AST) activity was lower in CG than in GSUB (P?<?0.05), and in the late postpartum period, AST activity was lower in CG than GSUB and GM (P?=?0.01). Somatic cell count was higher during the early and late postpartum periods for GM and GSUB when compared to CG (P?<?0.01). In this study, primiparous cows with low glucose and higher NEFA in the prepartum were more susceptible for mastitis in the early postpartum, probably due to low immune function associated to a more negative energy balance. In sum, increased prepartum serum NEFA concentration and decreased glucose in primiparous cows were associated with clinical mastitis incidence in the postpartum period.  相似文献   

Cattle Drive Salmonella Infection in the Wildlife–Livestock Interface     

G. Mentaberre  M. C. Porrero  N. Navarro‐Gonzalez  E. Serrano  L. Domínguez  S. Lavín 《Zoonoses and public health》2013,60(7):510-518

The genus Salmonella is found throughout the world and is a potential pathogen for most vertebrates. It is also the most common cause of food‐borne illness in humans, and wildlife is an emerging source of food‐borne disease in humans due to the consumption of game meat. Wild boar is one of the most abundant European game species and these wild swine are known to be carriers of zoonotic and food‐borne pathogens such as Salmonella. Isolation of the pathogen, serotyping and molecular biology are necessary for elucidating epidemiological connections in multi‐host populations. Although disease management at population level can be addressed using a number of different strategies, such management is difficult in free‐living wildlife populations due to the lack of experience with the wildlife–livestock interface. Herein, we provide the results of a 4‐year Salmonella survey in sympatric populations of wild boar and cattle in the Ports de Tortosa i Beseit National Game Reserve (NE Spain). We also evaluated the effects of two management strategies, cattle removal and increased wild boar harvesting (i.e. by hunting and trapping), on the prevalence of the Salmonella serovar community. The serovars Meleagridis and Anatum were found to be shared by cattle and wild boar, a finding that was confirmed by 100% DNA similarity patterns using pulse field gel electrophoresis. Cattle removal was more efficient than the culling of wild boar as a means of reducing the prevalence of shared serotypes, which underlines the role of cattle as a reservoir of Salmonella for wild boar. To our knowledge, this is the first attempt to manage Salmonella in the wild, and the results have implications for management.  相似文献   

The seroprevalence of canine respiratory coronavirus and canine influenza virus in dogs in New Zealand     

O Knesl  FJ Allan  S Shields 《New Zealand veterinary journal》2013,61(5):295-298

Abstract

AIM: To determine whether canine respiratory coronavirus (CRCoV) and canine influenza virus (CIV) are present in dogs in New Zealand.

METHODS: Serum samples from 251 dogs of varying age, breed and clinical histories were tested for the presence of antibodies to CRCoV and CIV, using indirect fluorescent antibody (IFA) analysis. The population sampled represented a wide geographic area but principally encompassed the central and lower North Island of New Zealand.

RESULTS: Seventy-three of the 251 samples (29%) were seropositive for CRCoV. Dogs <2 years old were less likely to be seropositive for CRCoV than older dogs. None was seropositive for CIV.

CONCLUSIONS: This study revealed the presence of antibodies to CRCoV in dogs in New Zealand. Young dogs are less likely to be seropositive than older dogs, probably due to increased opportunity for exposure to CRCoV over time. Serum antibodies to CIV were not detected in any of the dogs sampled, suggesting that this virus is unlikely to be present in dogs in New Zealand.

CLINICAL RELEVENCE: Canine respiratory coronavirus is present in New Zealand. Although the role of this virus in canine infectious tracheobronchitis has not been fully elucidated, evidence suggests that it may have a causal role in this disease. Veterinarians should consider CRCoV as a differential diagnosis in cases of respiratory disease in dogs in New Zealand. While CIV appears not to be currently present in New Zealand, veterinarians should consider infection with this virus as a differential diagnosis in dogs presenting with respiratory signs.  相似文献   

A hydrothermal seedling emergence model for Conyza bonariensis     

C Zambrano‐Navea  F Bastida  J L Gonzalez‐Andujar 《Weed Research》2013,53(3):213-220

Conyza bonariensis is a South American native annual Asteraceae that has been introduced to the Mediterranean, where it behaves as a ruderal plant and a weed that is difficult to control in several crops. The development of predictive models can contribute to control measures at early growth stages, but currently there are no studies to predict seedling emergence of Conyza species. Our objectives were to develop and evaluate a model for predicting emergence response of C. bonariensis to the soil hydrothermal environment. A hydrothermal seed germination model was fitted to time course germination data from germination tests carried out at different constant temperatures and water potentials with the aim of establishing the hydrothermal parameters characterising C. bonariensis seed germination. The relationship between cumulative seedling emergence and cumulative hydrothermal time under field conditions was analysed using the Gompertz function. Model development was based on 2 years' data from a field experiment. Base temperature and base water potential for seed germination were estimated at 10.6°C and ?0.70 ± 0.151 MPa, respectively. The emergence model showed a very good fit to the experimental data. According to this model, seedling emergence starts at 15 accumulated hydrothermal time (HTT) after sowing, and 50 and 95% emergence is completed at 53 HTT and 105 HTT, respectively. For model evaluation, independent field experiments were carried out in two localities. Cumulative seedling emergence was accurately predicted by the model. Results indicate that this model can be useful as a predictive tool contributing to effective control of C. bonariensis populations.  相似文献   

Development and evaluation of a model for predicting Lolium rigidum emergence in winter cereal crops in the Mediterranean area     

J Izquierdo  F Bastida  J M Lezaún  M J Sánchez del Arco  J L Gonzalez‐Andujar 《Weed Research》2013,53(4):269-278

Lolium rigidum is an extremely competitive and prevalent grass weed in cereal fields of Mediterranean areas. The proper timing of control measures is a prerequisite to maximising herbicide efficacy, in terms of both improved control and reduced herbicide inputs. The development of models to predict emergence flushes will contribute to this goal. Pooled cumulative emergence data obtained during three seasons from a cereal field were used to develop a Gompertz model. This explained relative seedling emergence from crop sowing onwards as a function of: (i) standard soil thermal time accumulation (TT) with a base temperature of 1.8°C and (ii) soil thermal time accumulation corrected for soil moisture (cTT). For the latter, no thermal time accumulation was computed for days in which the soil water balance within the upper 10‐cm soil layer indicated no water available for plants, because evapotranspiration was greater than rainfall plus the stored water remaining from the previous day. The model was validated with six datasets from four different sites and seasons. Compared with TT, the model based on cTT showed better performance in predicting L. rigidum emergence, particularly in predicting the end of emergence. Complemented with in‐field observations to minimise deviations, the model may be used as a predictive tool to better control this weed in dryland cereal fields of Mediterranean climate areas.  相似文献   

Increasing and stabilizing β-sheet structure of maize zein causes improvement in its rheological properties     

Mejia CD  Gonzalez DC  Mauer LJ  Campanella OH  Hamaker BR 《Journal of agricultural and food chemistry》2012,60(9):2316-2321

Wheat gluten proteins are considered to have the unique ability to form viscoelastic matrices that are essential for breadmaking. This study shows that maize seed storage protein (zein), if properly treated, can be made to function similarly to gluten at the protein secondary structure level with concomitant improved viscoelasticity. Here, we propose the concept of a small amount of coprotein (high molecular weight glutenin or casein) acting to stabilize a build-up of β-sheet structure in a zein-based dough, thus creating a viscoelastic matrix that is retained over time. This discovery is relevant to the need for gluten replacement viscoelastic proteins for wheat intolerant individuals and as well opens possibilities of creating wheatlike cereal varieties that could more cheaply substitute for wheat imports in developing countries.  相似文献   

Kinetics and binding capacity of six soils for structurally defined hydrolyzable and condensed tannins and related phenols     

Michael A. Schmidt  Jonathan J. Halvorson  Javier M. Gonzalez  Ann E. Hagerman 《Journal of Soils and Sediments》2012,12(3):366-375

Purpose  

We investigated tannin–soil interactions by assessing the kinetics of sorption and sorption capacities, and their relationship to the chemical properties of six polyphenolic compounds and the textures of six soils. We developed a new extraction procedure for recovering tannins from soil samples by successive extraction with solvents of decreasing polarity.  相似文献